Problem: If $a + b + c = 7$ and $x + y + z = 1$, what is $-8y - 2b - 2c - 8x - 8z - 2a$ ?
Explanation: $= -2a - 2b - 2c - 8x - 8y - 8z$ $= (-2) \cdot (a + b + c) + (-8) \cdot (x + y + z)$ $= (-2) \cdot (7) + (-8) \cdot (1)$ $= -14 - 8$ $= -22$